Nonsurgical reperfusion in evolving myocardial infarction.

Nonsurgical recanalization of the occluded coronary artery has been performed in patients with evolving myocardial infarction since the late 1970s by intracoronary administration of thrombolytic agents at the ostium of the occluded artery or directly to the site of occlusion. The authors review the basic concepts underlying intracoronary thrombolysis, the method applied at their institution and the clinical results. Reperfusion of totally occluded arteries or termination of the ischemic state in subtotally occluded arteries was achieved in 71 (87.7%) of 81 patients. Reocclusion occurred in four patients, in three of these at a time when anticoagulation became temporarily ineffective, emphasizing the need for uninterrupted anticoagulation with a partial thromboplastin time longer than 80 seconds. Thallium scintigraphic studies before and after reperfusion showed a decrease in defect, indicating myocardial salvage, in the successful cases but not in failures or untreated control subjects. A decrease in thallium-201 defect was followed by improvement of regional wall motion and usually also left ventricular ejection fraction. Three of the patients with an unsuccessful result and one patient with a successful result died. Bypass surgery was performed electively in 18 patients because of multiple vessel involvement. Intracoronary thrombolysis appears to be a relatively safe and promising procedure. A large controlled study will be needed for definitive assessment of its role in the management of acute myocardial infarction.

Piretanide, a potent diuretic with potassium-sparing properties, for the treatment of congestive heart failure.

The diuretic and clinical efficacy and safety of piretanide, a new high-ceiling loop diuretic, was determined in patients with mild to moderately severe congestive heart failure. Piretanide (n = 20) administered orally in a daily dosage of up to 24 mg was compared with placebo (n = 18) for 28 days, using a double-blind, randomized, parallel design. Patients were hospitalized during the first 5 days of the study when dosage titration was established and 24-hour fractionated urine collections were obtained. Piretanide caused significant diuresis for 3 hours after ingestion with a natriuretic response noted for up to 6 hours. While occasional kaliuretic response was noted, it did not significantly increase 24-hour urinary potassium excretion. Only one patient treated with the highest allowed dose of piretanide developed mild hypokalemia. An improvement in New York Heart Association functional class status was noted after piretanide therapy. In contrast, patients who received placebo exhibited no significant improvement. BUN increased in nine piretanide-treated patients; two were discontinued from the study because of progressive azotemia. However, there was no significant increase in serum creatinine levels. Other blood, physical, ECG, and audiometric examinations also revealed no significant abnormalities. The study suggests that oral piretanide is a relatively safe and effective diuretic for treating congestive heart failure with a potential advantage of having potassium-sparing properties.

Ventricular aneurysm: cross-sectional echocardiographic approach.

Current angiographic indexes of ventricular function have proved inadequate for prognostication in patients with ventricular aneurysm. Cross-sectional echocardiography can visualize residual myocardium in all four walls of the left ventricle. A new echocardiographic technique of calculating residual myocardium is presented. The echocardiographic technique yielded identical information to that of contrast angiography (r = 0.97). An index of residual myocardium was generated from the cross-sectional echocardiogram that correlated with the clinical state of the patients. In patients treated medically it predicted those patients likely to die within 6 months (p < 0.005). Preliminary observations in patients having aneurysmectomy revealed that there were good surgical results in those with an index of residual myocardium of 0.42 or greater, but more patients are necessary to establish the lower limit of a surgically acceptable level of residual myocardium.

Echocardiographic interpretation in the presence of Swan-Ganz intracardiac catheters.

Swan-Ganz balloon flotation catheters can produce strong echoes in the right heart. These echoes have variable configurations and can mimic right heart structures; their reverberations can be confused with left heart structures.

Quantitative exercise thallium-201 rotational tomography for evaluation of patients with prior myocardial infarction.

The utility of stress-redistribution thallium-201 myocardial perfusion single-photon emission computed tomography (SPECT) in patients with a prior single myocardial infarction was studied in 66 patients who were tested by both SPECT and coronary angiography. SPECT was quantified by comparing the patients' circumferential count profiles to a previously established normal data base and by plotting the results onto a polar coordinate map that localized defects to the 3 major coronary artery territories. The pattern of reversibility of the quantitatively detected defects was assessed by consensus visual analysis. SPECT thallium-201 detected myocardial infarction in 62 of 66 patients (sensitivity = 94%). Sixty-five percent of the infarct zones showed some reversibility at 4-hour imaging which corresponded with angiographic evidence of flow to the infarct zones in 95.5% of cases. Late (18 to 24 hours) imaging, done in 26 patients, showed complete or partial reversibility of 29% of infarct zone segments which were nonreversible on 4-hour images. To improve specificity for detection of disease in coronary arteries supplying the non-infarct territories, new quantitative criteria were developed that took into consideration contiguity of defects with the infarct zone. Accuracy for detection of patients with multivessel coronary disease by quantitative thallium-201 SPECT was 86%, which was significantly higher than those of the clinical response to exercise (48%), the exercise electrocardiographic response (56%) or their combination (65%).(ABSTRACT TRUNCATED AT 250 WORDS)

Improvement in regional and global left ventricular function after intracoronary thrombolysis: assessment with two-dimensional echocardiography.

After acute myocardial infarction, 23 patients undergoing intracoronary thrombolysis and 10 patients receiving conventional medical treatment were studied by 2-dimensional echocardiography to determine changes in regional and global left ventricular (LV) performance. Both quantitative and qualitative analysis of echocardiographic studies showed improvement in regional and global LV function in 18 patients with successful reperfusion immediately after thrombolysis to 10 days later (p less than 0.0005). Eleven patients who were studied before thrombolysis demonstrated no change in regional or global LV function immediately after thrombolysis. LV function did not improve in the conventionally treated group. These data indicate that in patients with acute coronary artery occlusion successfully reperfused by intracoronary thrombolysis, regional and global LV function improved by day 10 but not immediately after reperfusion.

Intravenous streptokinase in evolving acute myocardial infarction.

Eighty-one consecutive patients presenting within 3 hours of the onset of acute myocardial infarction (AMI) and without contraindications to thrombolytic or anticoagulant therapy received a 15- to 30-minute intravenous infusion of 750,000 or 1.5 million units of streptokinase (STK) followed by anticoagulation. Treatment was instituted 130 +/- 41 minutes after the onset of symptoms and reperfusion was achieved 36 +/- 26 minutes later. Reperfusion of the "infarct artery" was recognized by indirect clinical criteria in 78 patients (96%). In all 66 patients who underwent coronary angiography 3 to 7 days later, there was complete concordance between indirect and angiographic evidence of reperfusion. In 6 patients there was early reocclusion within 24 hours of treatment; in 4 of these patients, the artery was reopened with an additional dose of STK. Two elderly patients suffered an intracranial hemorrhage and there were 8 other major hemorrhagic complications, of which 7 were related to procedural trauma. Five patients (6.2%) died in the hospital. The results of intravenous STK thrombolytic therapy are compared with those of our previous study using intracoronary STK.

Paradoxical motion of the posterior left ventricular wall seen in healthy subjects in the upright position.

Paradoxical motion of the posterior left ventricular wall in patients in the upright but not in the supine position was demonstrated in a high percentage of normal volunteers. There was no significant difference in age, body surface area, heart rate, and blood pressure between the groups, with or without paradoxical motion. This echocardiographic finding probably represents a physiologic phenomenon and should be taken into consideration during the interpretation of upright exercise echocardiograms.

Simultaneous assessment of segmental and global left ventricular function by two-dimensional echocardiography in acute myocardial infarction.

Both segmental and global left ventricular performance were assessed simultaneously in 29 patients with acute myocardial infarction using two-dimensional echocardiography. Comparisons were made between left ventricular wall motion versus peak CK-MB, site of infarction, and occurrence of heart failure. Two-dimensional echocardiography identified areas of dyssynergy which corresponded to electrocardiographic areas of infarction in 89% of all cases. Patients with heart failure had more dyssynergic segments, and these segments manifested more severe dyssynergy than patients without heart failure. Patients with severe global dysfunction manifested higher peak CK-MB values, and those with anterior infarction had more global dyssynergy than did those patients with inferior infarction. These observations suggest that two-dimensional echocardiography is a useful technique for localization and assessment of segmental and global dyssynergy in acute myocardial infarction. Information so derived correlates with the clinical status of patients with acute myocardial infarction, and may offer important insights into both prognosis and treatment.

Lignocaine: a new technique for intravenous administration.

Current practices of intravenous lignocaine administration may result in a significant drop in blood level between the peak serum level from the initial bolus and the subsequent steady state from the constant infusion. This can cause a significant interval when plasma lignocaine levels are less than therapeutic, and ventricular ectopy may occur. To eliminate this subtherapeutic interval, a new therapeutic approach was devised. Seven patients were studied who had no evidence of congestive heart failure or liver disease. Lignocaine was infused at a rate of 25 mg/min; infusion dosages were selected by patient weight. The above therapeutic regimen eliminated the subtherapeutic hiatus and did not result in clinical toxicity. Therefore, this new infusion technique has significant clinical advantages in patients who require therapy with intravenous lignocaine.

Relationship between segmental abnormalities and global left ventricular function in coronary artery disease: validation of a theoretical model.

A theoretical model of the heart, which suggests a direct relationship between segmental abnormalities of left ventricular (LV) wall motion (WM) and LV ejection fraction (EF), was tested using two-dimensional echocardiography (2DE) and multiple-gated equilibrium blood pool scintigraphy (MGES) in a population of 25 coronary artery disease patients. MGES was used to determine EF, and 2DE was used to develop a method of analysis of LV segmental WM abnormalities. Two orthogonal apical 2DE views were analyzed. The length of the end-diastolic segments in which normal contraction occurred during systole were measured in each view, summed and divided by the sum of the end-diastolic silhouette lengths. The fraction thus created was multiplied by 100 and defined as the percentage of normally contracting myocardium (%NCM). %NCM correlated well with EF determined by MGES (r = 0.94). Determination of %NCM was highly reproducible for the same observer (r = 0.98), as well as for two observers (r = 0.98), and the standard error of estimate was low in both cases (4%). These findings, in addition to confirming the theoretical model, provide a new technique to assess LV segmental WM abnormalities by 2DE.

Utility of echocardiography for the early assessment of patients with nondiagnostic chest pain.

A two-dimensional (2D) echocardiogram was recorded shortly after admission in 46 patients with nondiagnostic chest pain. Eighteen patients were studied during chest pain and 28 were studied following the resolution of chest pain. Of the 18 patients studied during chest pain, six of the eight patients who had a regional wall motion abnormality (RWMA) evolved an acute infarction and the remaining two patients had evidence of significant coronary artery disease. Only 1 of 10 patients without a RWMA evolved an infarction and none had significant coronary artery disease. Of the 28 patients studied following the resolution of chest pain, 8 of the 10 patients with a RWMA evolved an acute infarction and one patient had evidence of significant coronary artery disease, whereas of 18 patients without a RWMA, none evolved an acute infarction and five had evidence of significant coronary artery disease. These data suggest that in patients presenting with nondiagnostic chest pain, an early assessment of regional wall motion by 2D echocardiography can reliably differentiate patients with myocardial ischemia or early infarction from patients with nonischemic chest pain when performed during an episode of chest pain; can also identify those patients with early acute myocardial infarction, even when performed following the resolution of chest pain; but is not useful for the detection of patients with significant coronary artery disease without infarction when performed following the resolution of chest pain.

Early diagnosis of nontransmural myocardial infarction by two-dimensional echocardiography.

Thirty patients with chest pain syndromes were studied on admission by two-dimensional echocardiography (2DE) to confirm or exclude acute myocardial infarction (AMI). Twelve patients suffered nontransmural AMI and 18 patients had no AMI. There was no significant difference between these groups in background characteristics. 2DE studies were analyzed quantitatively and qualitatively. The most sensitive and specific technique for detecting AMI was qualitative analysis, using the presence of severe hypokinesis as the criterion for an abnormal study. Using this technique, 10 of 12 patients (83%) with AMI and all 18 patients (100%) without AMI were correctly identified. This analysis technique was highly reproducible. These data indicate that in patients with chest pain syndromes without diagnostic ECG findings of AMI, 2DE may provide a rapid, sensitive, specific tool to aid in the establishment of the correct diagnosis. In patients with nontransmural AMI, the presence of severe hypokinesis appears to be the best discriminator of myocardial infarction.

Thallium-201 stress redistribution abnormalities of the right ventricle: a manifestation of proximal right coronary artery stenosis.

Thallium imaging in conjunction with electrocardiographic stress testing has become a widely utilized method for evaluating the presence and location of coronary artery disease. The literature has emphasized the appearance of the left ventricle with little mention of the right ventricle. This report presents the initial demonstration of abnormal right ventricular myocardial radionuclide visualization due to right coronary artery stenosis, as exemplified in two patients. In both patients a perfusion defect was documented in the free wall of the right ventricle with early redistribution imaging showing reversibility of these defects. Both patients were found to have proximal stenosis of the right coronary artery at cardiac catheterization. Thereby, the appearance of the free right ventricular wall on thallium imaging may provide useful additional information regarding presence and location of right coronary artery stenosis.